John F. Tooker

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Induced plant defenses in response to herbivore attack are modulated by cross-talk between jasmonic acid (JA)- and salicylic acid (SA)-signaling pathways. Oral secretions from some insect herbivores contain effectors that overcome these antiherbivore defenses. Herbivores possess diverse microbes in their digestive systems and these microbial symbionts can(More)
The ability of caterpillar or moth 'footsteps' to elicit defenses in the tomato (Solanum lycopersicum) plant was examined. Although touch responses frequently have been observed in plants, the role of herbivore 'touch' in eliciting antiherbivore defenses has not been adequately examined. A combination of methods, including in situ hybridization, reverse(More)
The use of mixtures of transgenic insecticidal seed and nontransgenic seed to provide an in-field refuge for susceptible insects in insect-resistance-management (IRM) plans has been considered for at least two decades. However, the U.S. Environmental Protection Agency has only recently authorized the practice. This commentary explores issues that(More)
Caterpillars produce oral secretions that may serve as cues to elicit plant defenses, but in other cases these secretions have been shown to suppress plant defenses. Ongoing work in our laboratory has focused on the salivary secretions of the tomato fruitworm, Helicoverpa zea. In previous studies we have shown that saliva and its principal component glucose(More)
While plant galls can be induced by a variety of organisms, insects produce the most diverse and complex galls found in nature; yet, how these galls are formed is unknown. Phytohormones have long been hypothesized to play a key role in gall production, but their exact role, and how they influence galls, has been unclear. Research in the past decade has(More)
In social groups, dominant individuals may socially inhibit reproduction of subordinates using aggressive interactions or, in the case of highly eusocial insects, pheromonal communication. It has been hypothesized these two modes of reproductive inhibition utilize conserved pathways. Here, we use a comparative framework to investigate the chemical and(More)
Parasitic species can dramatically alter host traits. Some of these parasite-induced changes can be considered adaptive manipulations that benefit the parasites. Gall-inducing insects are parasites well known for their ability to alter host-plant morphology and physiology, including the distribution of plant defensive compounds. Here it was investigated(More)
Insect oviposition on plants frequently precedes herbivory. Accumulating evidence indicates that plants recognize insect oviposition and elicit direct or indirect defenses to reduce the pressure of future herbivory. Most of the oviposition-triggered plant defenses described thus far remove eggs or keep them away from the host plant or their desirable(More)
We describe a previously uncharacterized function for changes in plant chemistry induced by phytophagous insects: to provide cues for mate location. Larvae of the gall wasp Antistrophus rufus Gillette (Hymenoptera: Cynipidae) feed within inconspicuous galls inside the flowering stems of the prairie perennials Silphium laciniatum L. and Silphium(More)